Internal combustion engine intake and exhaust systems

Abstract

An intake system (3, 4, 9) for a reciprocating internal combustion engine adapted to control operation of the engine to produce a high level of torque across a wide range of engine revolutions. The intake system is formed by a plenum (3) feeding a plurality of manifold tubes (4) dimensioned so as to improve volumetric efficiency of the engine by inducing ram air effects in a naturally aspirated engine over a wide range of rotational speeds.

I claim: 
     
       1. A reciprocating piston internal combustion engine comprising: at least one cylinder having a cylinder wall, at least one intake port and at least one exhaust port, the ports being disposed on the cylinder wall;   at least one intake valve disposed at a corresponding intake port for regulating a flow of intake gas into the cylinder;   at least one exhaust valve disposed at a corresponding exhaust port for regulating a flow of exhaust gas out of the cylinder;   a piston in the cylinder mounted for reciprocal motion within the cylinder, the piston further being adapted to assume a bottom dead center position and a top dead center position; and   a plurality of manifold tubes comprising: a least one intake manifold tube connected to a corresponding intake port;   at least one exhaust manifold tube connected to a corresponding exhaust port;     wherein each of the intake manifold tubes comprises a plurality of pipes connected end to end and including an end pipe disposed closest to a corresponding port, each of the pipes having a constant cross-section, the cross section of the pipes increasing incrementally in a direction away from the end pipe, and a tapered portion being connected to the end pipe at the exit end thereof, and to an adjacent one of the pipes at the entry end thereof; and   further including a plenum chamber device comprising an intake manifold, the intake manifold having at least one manifold outlet connected to a corresponding intake manifold tube, the plenum chamber device thereby being disposed upstream of and in flow communication with the intake port.   
     
     
       2. The reciprocating piston internal combustion engine according to claim 1 wherein: at least one intake port includes a plurality of intake ports; and   the plenum chamber device is divided into two similar chambers.   
     
     
       3. The reciprocating piston internal combustion engine according to claim 2 further including a plate for dividing the plenum chamber device into the two similar chambers, the plate having at least one balancing hole at a central region thereof. 
     
     
       4. The reciprocating piston internal combustion engine according to claim 3 wherein the balance hole is radiused. 
     
     
       5. The reciprocating piston internal combustion engine according to claim 1 wherein the intake manifold of the plenum chamber device includes a manifold inlet located at a top center region thereof, and internal manifold walls defining smooth radiused transitions from the manifold inlet to the manifold outlet. 
     
     
       6. The reciprocating piston internal combustion engine according to claim 1 wherein: at least one intake port includes a plurality of intake ports;   at least one manifold outlet includes a plurality of manifold outlets each corresponding to a respective intake manifold tube, at least one of the plurality of manifold outlets meeting its respective manifold tube at a right angle thereto, the respective manifold tube further meeting its respective intake port at a right angle thereto, the respective manifold tube being thereby curved.   
     
     
       7. The reciprocating piston internal combustion engine according to claim 6 wherein: the plurality of intake ports include at least four intake ports;   at least one intake manifold tube includes at least two intake manifold tubes leading to the two chambers of the plenum chamber device.   
     
     
       8. The reciprocating piston internal combustion engine according to claim 7 wherein at least one intake manifold tube includes a first pipe connected to a second pipe which is in turn connected to a third pipe, the third pipe being the end pipe, a cross section of the first pipe being larger than a cross section of the second pipe and the cross section of the second pipe being larger than a cross section of the third pipe, at least one intake manifold tube further including tapered portions disposed to connect the first pipe to the second pipe and the second pipe to the third pipe for providing a smooth flow transition into each of the pipes. 
     
     
       9. The reciprocating piston internal combustion engine according to claim 7 wherein: each of the two intake manifold tubes includes two tertiary pipes of constant cross section and one secondary pipe of constant cross section joined to the two tertiary pipes such that the tertiary pipes form a fork with respect to the secondary pipe, each of the tertiary pipes being a respective end pipe;   the plurality of manifold tubes further includes a primary pipe of constant cross section joined to the secondary pipes of the two intake manifold tubes such that the secondary pipes form a fork with respect to the primary pipe, the cross section of the primary pipe being larger than the cross section of the secondary pipes, and the cross section of the secondary pipes being larger than the cross section of the tertiary pipes; and   the tapered portion of each of the two intake manifold tubes is a first tapered portion, each of the two intake manifold tubes further including a second tapered portion connecting the secondary pipes to the primary pipe for providing a smooth flow transition into each of the pipes.   
     
     
       10. The reciprocating piston internal combustion engine according to claim 7 wherein: the two chambers of the plenum chamber device are located centrally, and vertically above the intake manifold;   the tapered portion is a first tapered portion, each of the manifold tubes further including a second tapered portion having an entry end and an exit end, a cross section of the exit end being larger than a cross section of the entry end; and   one of the plurality of pipes is a curved pipe connecting the entry end of the second tapered portion to at least one of the two chambers of the plenum chamber.   
     
     
       11. The reciprocating piston internal combustion engine according to claim 7 wherein: the two chambers of the plenum chamber device are disposed at opposite sides of at least one cylinder;   the tapered portion is a first tapered portion, each of the manifold tubes further including a second tapered portion having an entry and an exit end, a cross section of the exit end being larger than a cross section of the entry end; and   one of the plurality of pipes provides a smooth flow transition connecting the entry end of the second tapered portion to at least one of the two chambers of the plenum chamber.   
     
     
       12. A reciprocating piston internal combustion engine comprising: at least one cylinder having a cylinder wall, at least one intake port and at least one exhaust port, the ports being disposed on the cylinder wall;   at least one intake valve disposed at a corresponding intake port for regulating a flow of intake gas into the cylinder;   at least one exhaust valve disposed at a corresponding exhaust port for regulating a flow of exhaust gas out of the cylinder;   a piston in the cylinder mounted for reciprocal motion within the cylinder, the piston further being adapted to assume a bottom dead center position and a top dead center position; and   a plurality of manifold tubes comprising: at least one intake manifold tube connected to a corresponding intake port;   at least one exhaust manifold tube connected to a corresponding exhaust port;     a plenum chamber device comprising an intake manifold, the intake manifold having at least one manifold outlet connected to a corresponding intake manifold tube, the plenum chamber device thereby being disposed upstream of and in flow communication with the intake port, wherein     each of the intake manifold tubes comprises a plurality of pipes connected end to end and including an end pipe disposed closest to a corresponding intake port: and   the plurality of pipes further includes at least one tapered tube connected at a large end thereof to the plenum chamber and at a smaller end thereof to the end pipe, the tapered tube being longer than the end pipe.